b 1. Field of the Invention
The present invention is directed to video display security systems and more particularly to a system for optically masking a display image and selective removal of the mask for secure viewing of the display.
2. Discussion of the Prior Art
The widespread use of laptop computers has enabled users to access information in also any location. Often, information is retrieved during meetings or while traveling between destinations where many other people besides the user may view the display. A problem arises where the information displayed is confidential and should be seen only by the user.
While information security systems that provide various levels of security to multiple users on a network, such as that shown in U.S. Pat. No. 4,881,179, provide selected access to information, these systems do not protect unauthorized viewing of the information while it is being displayed. U.S. Pat. No. 4,859,994 is directed to a system for providing selected viewing of a display to allow hearing impaired persons to view subtitles while others cannot see the subtitles. A liquid crystal display that produces the subtitles as polarized light can be seen only by viewers having polarized eyeglass lenses. Although selective viewing is provided, it is not secure viewing in that anyone having polarized sunglasses can see the information on the screen. In addition, the selectivity is not switchable in the event security is no longer required.
Thus, there is a need for a system for providing secure, selective viewing of information on a display that can be easily enabled and disabled by the viewer.